Assessment of effectiveness of restoration projects in mangrove forests of Mbweni and Bacamoyo, Tanzania

This study assessed the effectiveness of mangrove restoration projects carried out at Mbweni fishing village, 30 km north of Dar es Salaam, and at Kaole fishing village, 5 km south of Bagamoyo Township, 60 km north of Dar es Salaam. These restored sites had been previously degraded by over-harvesting for building poles, firewood and charcoal making, as well as clear cutting in some areas for construction purposes. Mangrove canopy cover, basal area and growth rates were measured in experimental (restored) and control (un-restored) plots (each 5x5 m). In each study site, Mbweni A, Mbweni B and Kaole, 16 plots were examined. Temperature, salinity of interstitial water, organic matter and tidal inundation were also measured in each plot. In all three study sites, the contribution of replanted mangroves to both increase in canopy cover and basal area was significant, indicating that the community-based mangrove restoration projects have had significant positive impacts on mangrove abundance and diversity. It was also shown that the growth rates of mangroves replanted in community-based restoration projects a re as high as those mangroves that have regenerated naturally, thus showing that community-based restoration is very important and effective and should be encouraged. Moreover, there was significant positive correlation between transplanted mangrove growth and soil organic matter content, showing that restoration is likely to ensure an increase in soil organic matter. It is recommended that further support by governmental and non-govemmental organizations should be given to the restoration work being carried out by the environmental groups at Mbweni and Kaole, so that these projects can continue through future generations.